import java.util.Arrays;

public class HashBuck {

    static class Node{
        public int key;
        public int val;
        public Node next;

        public Node(int key,int val){
            this.key = key;
            this.val = val;
        }
    }

    public Node[] array = new Node[10];
    public int usedSize;

    public static final double DEFAULT_LOAD_FACTOR = 0.75f;

    public void push(int key, int val){
        int index = key%array.length;
        Node cur = array[index];
        while (cur != null){
            if (cur.key == key){
                cur.val = val;
                return;
            }
            cur = cur.next;
        }//说明当前没有这个key的节点

        Node node = new Node(key, val);
        node.next =array[index];
        array[index] = node;
        usedSize++;

        if (doLoadFactor() >=DEFAULT_LOAD_FACTOR){
            resize();
        }
    }

    //扩容
    private void resize() {
        //不能在当前数组进行扩容
        //array = Arrays.copyOf(array,2*array.length);//error

        //重新开辟一个数组
        Node[] newArray = new Node[2*array.length];

        for (int i = 0; i < array.length; i++) {
            Node cur = array[i];
            while (cur != null){
                int newIndex = cur.key % newArray.length;
                Node curN = cur.next;
                cur.next = newArray[newIndex];
                newArray[newIndex] = cur;
                cur = curN;
            }
        }
        array = newArray;
    }

    //判断是否扩容
    private double doLoadFactor(){
        return usedSize*1.0/array.length;
    }

    public int getVal(int key){
        int index = key % array.length;
        Node cur = array[index];
        while (cur != null){
            if (cur.key == key){
                return cur.val;
            }
            cur = cur.next;
        }
        return -1;
    }


}
